PHMSA Final Rule: Hazardous Materials: Adoption of Department of Transportation Special Permit 14175

This final rule removes undue regulatory burdens by adopting the provisions of U.S. Department of Transportation (DOT) special permit (SP) 14175 to authorize a 10-year requalification period and the ultrasonic examination (UE) testing method for DOT specification 3A and 3AA cylinders in flammable and non-flammable, nonpoisonous gas service. This adoption reflects advances in testing technology and will relieve stakeholders of the burden of performing more frequent cylinder requalification.

DATES: Effective September 3, 2026.

Published in the Federal Register August 4, 2026, 91 FR 49354.

View final rule.

§180.209 Requirements for requalification of specification cylinders.
(a)	Revised	View text
(b)	Revised	View text

Previous Text

§180.209 Requirements for requalification of specification cylinders.

(a) Periodic qualification of cylinders. Each specification cylinder that becomes due for periodic requalification, as specified in the following table, must be requalified and marked in conformance with the requirements of this subpart. Requalification records must be maintained in accordance with §180.215. Table 1 follows:

Table 1 to Paragraph (a)—Requalification of Cylinders ¹
Specification under which cylinder was made	Minimum test pressure (psig) ²	Requalification period (years)
¹ Any cylinder not exceeding two inches outside diameter and less than two feet in length is excepted from volumetric expansion test.
² For cylinders not marked with a service pressure, see §173.301a(b) of this subchapter.
³ Minimum test pressure is not applicable to those cylinders and tubes requalified using ultrasonic examination.
⁴ This provision does not apply to cylinders used for carbon dioxide, fire extinguisher, or other industrial gas service.
3	3000 psig	5.
3A, 3AA	5/3 times service pressure, except non-corrosive service (see §180.209(g))	5, 10, or 12 (see §180.209(b), (f), (h), and (j)).
3AL	5/3 times service pressure	5 or 12 (see §180.209(j) and (m)⁴ ).
3AX, 3AAX	5/3 times service pressure	5.
3B, 3BN	2 times service pressure (see §180.209(g))	5 or 10 (see §180.209(f)).
3E	Test not required
3HT	5/3 times service pressure	3 (see §§180.209(k) and 180.213(c)).
3T	5/3 times service pressure or UE³	5.
4AA480	2 times service pressure (see §180.209(g))	5 or 10 (see §180.209(h)).
4B, 4BA, 4BW, 4B–240ET	2 times service pressure, except non-corrosive service (see §180.209(g))	5, 7, 10, or 12 (see §180.209(e), (f), and (j)).
4D, 4DA, 4DS	2 times service pressure	5.
4E	2 times service pressure, except non-corrosive service (see §180.209(g))	5, 10, or 12 (see §180.209(e)).
4L	Test not required
8, 8AL		10 or 20 (see §180.209(i)).
Exemption or special permit cylinder	See current exemption or special permit, or UE ³ as allowed by CGA C–20 (2014)	See current exemption or special permit.
Foreign cylinder (see §173.301(j) of this subchapter for restrictions on use)	As marked on cylinder, but not less than 5/3 of any service or working pressure marking	5 (see §§180.209(l) and 180.213(d)(2)).

(b) DOT 3A or 3AA cylinders. (1) A cylinder conforming to specification DOT 3A or 3AA with a water capacity of 56.7 kg (125 lb) or less that is removed from any cluster, bank, group, rack, or vehicle each time it is filled, may be requalified every ten years instead of every five years, provided the cylinder conforms to all of the following conditions:

(i) The cylinder was manufactured after December 31, 1945.

(ii) The cylinder is used exclusively for air; argon; cyclopropane; ethylene; helium; hydrogen; krypton; neon; nitrogen; nitrous oxide; oxygen; sulfur hexafluoride; xenon; chlorinated hydrocarbons, fluorinated hydrocarbons, liquefied hydrocarbons, and mixtures thereof that are commercially free from corroding components; permitted mixtures of these gases (see §173.301(d) of this subchapter); and permitted mixtures of these gases with up to 30 percent by volume of carbon dioxide, provided the gas has a dew point at or below minus (52° F) at 1 atmosphere.

(iii) [Reserved]

(iv) The cylinder is dried immediately after hydrostatic testing to remove all traces of water.

(v) The cylinder is not used for underwater breathing.

(vi) Each cylinder is stamped with a five-pointed star at least one-fourth of an inch high immediately following the test date.

(2) If, since the last required requalification, a cylinder has not been used exclusively for the gases specifically identified in paragraph (b)(1)(ii) of this section, but currently conforms with all other provisions of paragraph (b)(1) of this section, it may be requalified every 10 years instead of every five years, provided it is first requalified and examined as prescribed by §173.302a(b) (2), (3) and (4) of this subchapter.

(3) Except as specified in paragraph (b)(2) of this section, if a cylinder, marked with a star, is filled with a compressed gas other than as specified in paragraph (b)(1)(ii) of this section, the star following the most recent test date must be obliterated. The cylinder must be requalified five years from the marked test date, or prior to the first filling with a compressed gas, if the required five-year requalification period has passed.

['General Packaging Requirements - Hazmat']

['Cylinders - Hazmat']

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